1. Field of the Invention
The present invention relates generally to reprogrammable automation devices, and more particularly to a self-contained mobile reprogrammable automation device
2. Description of the Prior Art
The automatic transportation of particular objects from point to point within an enclosed environment is desirable in a number of commercial, industrial, medical, and scientific settings. One such illustrative situation includes the transportation of cassettes filled with silicon wafers from machine to machine in a clean room of a semiconductor chip fabrication facility. Subsequent processing of the chips, for example encapsulation of the chips, may also be performed in a clean room and/or under semi-automatic conditions. Transportation of biohazardous or radioactive materials under commercial, industrial or research conditions is also common. The environments in which these materials are found and utilized typically constitute single large rooms, for example clean rooms or isolation rooms, which are maintained under controlled environmental conditions. Human manipulation is often contraindicated for reason of safety, cleanliness, labor costs, or to preclude handling mishaps.
These environments may have a number of machines, at fixed locations within the room, to which and from which objects must be transported. In the semiconductor chip fabrication process it is often necessary to transport cassettes filled with wafers to and from several different processing machines within a particular environment Depending on the types of chips being manufactured, the number and order of machines will vary. Thus a fixed transporation system, for example a continuous belt system may be impractical. Fixed belt systems may unduly crowd the workplace, creating difficulty with access to the equipment.
Accordingly, a preferred mode of wafer cassette transport within a fabrication clean room is a mobile transport unit (MTU), able to independently transfer the cassettes filled with wafers between machines as needed.
None of the prior art has addressed the issue of providing a independently operable, self-contained mobile transport unit able to operate within a particular isolated environment, and which is independently controllable, self-contained, and able to operate with sufficient precision to deliver cassettes filled with wafers to and from various machines without creating disturbances which would adversely effect the fabrication process.